Counter-terrorism police have arrested two men after the explosion of an ultra-low emission zone (Ulez) camera in south-east London damaged nearby vehicles and property. Officers from the Metropolitan police’s counter-terrorism command arrested a 60-year-old man from Sidcup and a 61-year-old man from Horsham on suspicion of conspiracy to cause an explosion likely to endanger life or property on Monday. The latter was also arrested on suspicion of criminal damage. Both remain in custody at a south London police station while searches are under way at two addresses, in Sidcup and Horsham, Scotland Yard said. The camera, which was installed on a Sidcup street on 6 December, was cut down about one and a half hours before it was blown up later that day. An earlier Met statement said the incident was caused by a “low-sophistication improvised explosive device”. Photos posted on social media by people living nearby showed a large dent in a van and damage to the window frame of a nearby house. No one was injured. DCS Trevor Lawry, the commander for the Bexley area, said: “The explosion could easily have had far more harmful consequences and today’s arrests highlight just how seriously the Met is treating the incident. “My local officers are continuing to work with and support the counter-terrorism command who are leading the investigation due to their specialism in dealing with incidents involving the use of explosives.” A spokesperson for the mayor of London, Sadiq Khan, also condemned the incident, describing it as “grotesquely irresponsible behaviour [that] puts both lives and property at risk”. The Ulez scheme aims to improve air quality by charging a £12.50 daily fee to enter the zone for vehicles that do not meet emissions standards – broadly, petrol cars from before 2005 and pre-2015 diesels. It is enforced by a network of numberplate recognition cameras. Khan’s decision to expand the Ulez area to cover the whole of Greater London from 29 August has faced intense opposition from the government, Conservative MPs and parts of the media. The scheme has also prompted a surge in vandalism. Figures released by the Met in November showed there had been nearly 1,000 recorded crimes connected to the cameras being stolen or vandalised in the past seven months.